Post navigation

Why Boris Johnson has got it wrong on Blackfriars Bridge

London’s Mayor Boris Johnson has made his position clear on Blackfriars Bridge, a subject that has become a major subject of campaigning for a more cycling-friendly city:

Question No: 1750 / 2011John Biggs: Would you support a 20MPH limit throughout the junction?

Written answer from the Mayor, received on 13 July 2011:

A temporary 20mph limit was introduced at the junction of Blackfriars only to accommodate the construction of the station, which has required a great deal of hoarding, resulting in the narrowing of road space. It has been necessary to redesign the junction in order to accommodate new pedestrian crossings and the hugely increased pedestrian flows into and out of the station once it reopens. The two new crossings will reduce traffic speeds through the junction such that the additional signage and other infrastructure necessary to post a 20mph limit would be redundant and it would not be of benefit when traffic is lower during the remainder of the day.

There is no evidence that speed was an issue at Blackfriars prior to the current station works, with only one speed related collision recorded since 2006. Modelling demonstrates that speed will not be an issue after the scheme is built.

Modelling of the revised format shows that traffic will travel at less than 20mph for the morning peak, the period which coincides with the highest cycling demand. TfL will closely monitor traffic speeds through the junction and will take action if it becomes clear that speed is an issue.

(Emphasis added)

Dr Robert Davis of the Road Danger Reduction Forum came on the show a couple of week’s ago. One of his arguments is that public policy is heavily skewed by a form of ambulance-chasing, i.e. only taking action on road danger when there is evidence in the form of collisions causing death and serious injuries. By only responding to data on crashes, Dr Davis says we ignore the adaptive behaviour that is going on among vulnerable road users like cyclists and pedestrians. We are presented with the apparent paradox that a road can be dangerous for cyclists yet be declared ‘safe’ since there have been no crashes involving cyclists. This is because cyclists have simply decided not to ride on that road.

Now, nobody can say that cyclists are refusing to ride over Blackfriars Bridge. On the contrary, cyclists outnumber motor vehicles during the morning rush hour. However, they are a certain kind of cyclist – confident, assertive, experienced. And many of this confident minority would say that riding over the Bridge is something they do with gritted teeth.

If Blackfriars Bridge feels like a motorway, we can assume that a large number of potential cyclists are being discouraged from riding over it.

If we want cycling to become a truly everyday mode of transport, open to everyone and not just the confident, athletic minority, then we need to make key routes like London’s bridges more inviting to every cyclist, and every potential cyclist. And this means paying attention to issues of speed, space and potential sources of danger, not hiding behind statistics that are skewed by the adaptive behaviour of the most vulnerable. It requires a complete overhaul of the design. Is this something that a Mayor who’s top transport priority is keeping motorised traffic moving smoothly is likely to countenance? I doubt it, though I would love to be proven wrong.

2 thoughts on “Why Boris Johnson has got it wrong on Blackfriars Bridge”

But surely it is off peak that the 20 mph limit is needed? I’m sure the 85th percentile speeds (ie 15% of drivers are faster than this figure) is about 35 or 40 mph on some bridges at night. Oh, yeah, Cyclists in the City posted on that a while ago although they got a bit confused and thought that 85% of drivers were travelling *at* that speed.